def relayreceiver(sock, fivetuple):
while True: # start the main listening loop of the udp server
try:
data, remote = (yield multitask.recvfrom(sock, maxsize)
) # receive a packet
if data:
if _debug: print 'server().recvfrom() from', remote
multitask.add(datahandler(sock1, data, remote))
except: # some other socket error, probably sock1 is closed.
break
if _debug: print 'server() exiting'
def relayreceiver(sock, fivetuple):
while True: # start the main listening loop of the udp server
try:
data, remote = (yield multitask.recvfrom(sock, maxsize)) # receive a packet
if data:
if _debug:
print "server().recvfrom() from", remote
multitask.add(datahandler(sock1, data, remote))
except: # some other socket error, probably sock1 is closed.
break
if _debug:
print "server() exiting"
def udpreceiver(self, maxsize=16386, timeout=None, interval=30):
'''A UDP receiver task which also performs network ack.'''
while True:
data, addr = yield multitask.recvfrom(self.udp, maxsize, timeout=timeout)
msg, remote = self.parse(data, addr, self.udp.type)
if not msg: continue # ignore invalid messages. TODO: handle non-p2p message
if _debug and msg.name[:4] != 'Hash': print self.name, 'udp-received %s=>%s: %r'%(remote.hostport, self.node.hostport, msg)
if 'ack' in msg and msg.name != 'Ack:Indication': # the remote requires an ack. send one.
del msg['ack'] # remove the ack
ack = dht.Message(name='Ack:Indication', hash=H(data)) # hash of original received packet
yield self.send(msg=ack, node=remote) # send the NetworkAck message
msg['remote'] = remote # put remote as an attribute in msg before putting on queue.
yield self.put(msg) # put the parsed msg so that other interested party may get it.
def receiveRTCP(self, sock):
try:
fd = sock.fileno()
while True:
data, remote = yield multitask.recvfrom(sock, self.maxsize)
if self.app: self.app.receivedRTCP(data, remote, self.srcRTCP)
except GeneratorExit:
pass # terminated
except:
print 'receive RTCP exception', (sys and sys.exc_info())
try:
os.close(fd)
except:
pass
def receiveRTCP(self, sock):
try:
fd = sock.fileno()
while True:
data, remote = yield multitask.recvfrom(sock, self.maxsize)
if self.app:
self.app.receivedRTCP(data, remote, self.srcRTCP)
except GeneratorExit:
pass # terminated
except:
print "receive RTCP exception", (sys and sys.exc_info())
try:
os.close(fd)
except:
pass
def mcastreceiver(self, maxsize=1500, timeout=None, interval=30):
while True:
if self.mcast is not None:
data, addr = yield multitask.recvfrom(self.mcast, maxsize, timeout=timeout)
msg, remote = self.parse(data, addr, self.mcast.type)
if not msg: print 'ignoring empty msg'; continue # ignore invalid message. TODO: handle non-p2p message
if remote == self.node:
if _debug: print 'ignoring our own multicast packet'
continue
if _debug: print self.name, 'mcast-received %s=>%s: %r'%(remote.hostport, self.nodemcast.hostport, msg)
if 'ack' in msg: del msg['ack'] # just remove ack, but don't send an ack for multicast
msg['remote'] = remote
msg['multicast'] = True # so that application knows that this is received on multicast
yield self.put(msg)
else:
yield dht.randomsleep(interval)
def _sipreceiver(self, stack, maxsize=16386):
'''Handle the messages or connections on the given SIP stack's socket, and pass it to the stack so that stack can invoke
appropriate callback on this object such as receivedRequest.'''
sock = stack.sock
while True:
if sock.type == socket.SOCK_DGRAM:
data, remote = yield multitask.recvfrom(sock, maxsize)
logger.debug('%r=>%r on type=%r\n%s', remote, sock.getsockname(), stack.transport.type, data)
if data:
try: stack.received(data, remote)
except: logger.exception('received')
elif sock.type == socket.SOCK_STREAM:
conn, remote = yield multitask.accept(sock)
if conn:
logger.debug('%r=>%r connection type %r', remote, conn.getsockname(), stack.transport.type)
if stack.transport.type in ('ws', 'wss'):
multitask.add(self._wsreceiver(stack, conn, remote, maxsize))
else:
multitask.add(self._tcpreceiver(stack, conn, remote, maxsize))
else: raise ValueError, 'invalid socket type'
def udpreceiver(self, maxsize=16386, timeout=None, interval=30):
'''A UDP receiver task which also performs network ack.'''
while True:
data, addr = yield multitask.recvfrom(self.udp,
maxsize,
timeout=timeout)
msg, remote = self.parse(data, addr, self.udp.type)
if not msg:
continue # ignore invalid messages. TODO: handle non-p2p message
if _debug and msg.name[:4] != 'Hash':
print self.name, 'udp-received %s=>%s: %r' % (
remote.hostport, self.node.hostport, msg)
if 'ack' in msg and msg.name != 'Ack:Indication': # the remote requires an ack. send one.
del msg['ack'] # remove the ack
ack = dht.Message(
name='Ack:Indication',
hash=H(data)) # hash of original received packet
yield self.send(msg=ack,
node=remote) # send the NetworkAck message
msg['remote'] = remote # put remote as an attribute in msg before putting on queue.
yield self.put(
msg
) # put the parsed msg so that other interested party may get it.
def mcastreceiver(self, maxsize=1500, timeout=None, interval=30):
while True:
if self.mcast is not None:
data, addr = yield multitask.recvfrom(self.mcast,
maxsize,
timeout=timeout)
msg, remote = self.parse(data, addr, self.mcast.type)
if not msg:
print 'ignoring empty msg'
continue # ignore invalid message. TODO: handle non-p2p message
if remote == self.node:
if _debug: print 'ignoring our own multicast packet'
continue
if _debug:
print self.name, 'mcast-received %s=>%s: %r' % (
remote.hostport, self.nodemcast.hostport, msg)
if 'ack' in msg:
del msg[
'ack'] # just remove ack, but don't send an ack for multicast
msg['remote'] = remote
msg['multicast'] = True # so that application knows that this is received on multicast
yield self.put(msg)
else:
yield dht.randomsleep(interval)
def server(sock1, **kwargs):
"""A simple server implementation to test the code or to use in real deployment.
The application should start the server as multitask.add(server(sock)).
The caller should make sure that the sock1 argument is a UDP or TCP socket
which is already bound. Additionally, sock2, sock3, and sock4 can be supplied
as keyword arguments and represent the socket to use for change-IP, change-port
and change IP+port commands respectively. Other keyword arguments are as follows:
timeout: optional acivity timeout (second) if relay is activated, defaults to 180.
external: optional external (ip, port) of the socket in case it is behind
a full-cone NAT and still acts as a (relay) server.
handler: optional function that gets invoked as handler(sock, remote, data) for
non-STUN data, and allows the application to demultiplex other types of data.
maxsize: optional maximum size of packet to handle, defaults to 1500."""
sock2, sock3, sock4 = kwargs.get("sock2", None), kwargs.get("sock3", None), kwargs.get("sock4", None)
addr1 = getlocaladdr(sock1)
addr4 = sock4 and getlocaladdr(sock4) or None
timeout = kwargs.get("timeout", 180) # three minutes
external = kwargs.get("external", addr1)
handler = kwargs.get("handler", None)
maxsize = kwargs.get("maxsize", 1500)
tcp = sock1.type == socket.SOCK_STREAM # whether the server is on tcp or udp.
binding = dict() # allocated relay bindings if any
def respond(sock, data, remote):
if sock.type == socket.SOCK_STREAM:
yield multitask.send(sock, data)
else:
yield multitask.sendto(sock, data, remote)
def bindingRequest(sock, m, remote): # Serve a binding request of STUN
res = Message()
res.method, res.type, res.tid = Message.BINDING, Message.RESPONSE, m.tid
mapped = Attribute(Attribute.MAPPED_ADDRESS) # mapped-address attribute
mapped.address = (sock.family, addr1[0], addr1[1])
res.attrs.append(mapped)
if Attribute.CHANGE_REQUEST not in m: # send from same address:port
if addr4: # add the other address attribute
other = Attribute(Attribute.OTHER_ADDRESS)
other.address = (sock4.family, addr4[0], addr4[1])
res.attrs.append(other)
else:
change = m[Attribute.CHANGE_REQUEST]
sock = (
change.value == "\x00\x00\x00\x06"
and sock4
or change.value == "\x00\x00\x00\x02"
and sock3
or change.value == "\x00\x00\x00\x04"
and sock2
or None
)
if sock:
yield respond(sock, str(res), remote)
raise StopIteration()
def allocateRequest(sock, m, remote): # serve the allocate request of TURN
fivetuple = (sock.type, getlocaladdr(sock), remote)
lifetime = timeout
if Attribute.LIFETIME in m:
lt = struct.unpack("!L", m[Attribute.LIFETIME].value)
if lt < lifetime:
lifetime = lt
if fivetuple in binding: # already found
newsock = binding[fivetuple]
if lifetime == 0: # terminate the binding
del binding[fivetuple]
del binding[newsock]
else:
if lifetime > 0: # allocate, otherwise it is already missing.
newsock = socket.socket(sock.family, sock.type)
newsock.bind(("0.0.0.0", 0)) # bind to any
binding[newsock] = fivetuple
binding[fivetuple] = newsock
res = Message()
res.method, res.type, res.tid = m.method, Message.RESPONSE, m.tid
mapped = Attribute(Attribute.MAPPED_ADDRESS) # mapped-address attribute
mapped.address = (newsock.family, (external, newsock and newsock.getsockname()[1] or 0))
res.attrs.append(mapped)
res.attrs.append(Attribute(Attribute.LIFETIME, struct.pack("!L", lifetime)))
if lifetime == 0 and newsock: # close any previous listening function
newsock.close() # this should trigger close of functions
else:
if sock.type == socket.SOCK_STREAM:
multitask.add(relayaccepter(newsock, fivetuple))
else:
multitask.add(relayreceiver(newsock, fivetuple))
yield respond(sock, str(res), remote)
def relaytcpreceiver(sock, fivetuple):
pass
def relayaccepter(sock, fivetuple):
sock.listen(5) # accept queue
while True: # start the main listening loop of the tcp server
try:
conn, remote = (yield multitask.accept(sock))
if conn:
if _debug:
print "relayaccepter().accept() from", remote
sock.close() # close the original listening socket -- no more connections
binding[fivetuple] = conn # update the binding
del binding[sock]
binding[conn] = fivetuple
multitask.add(relaytcpreceiver(conn, fivetuple, remote))
break
except: # some other socket error, probably sock is closed.
break
if _debug:
print "relaytcpaccepter() exiting"
def relayreceiver(sock, fivetuple):
while True: # start the main listening loop of the udp server
try:
data, remote = (yield multitask.recvfrom(sock, maxsize)) # receive a packet
if data:
if _debug:
print "server().recvfrom() from", remote
multitask.add(datahandler(sock1, data, remote))
except: # some other socket error, probably sock1 is closed.
break
if _debug:
print "server() exiting"
def sendRequest(sock, m, remote): # serve the send request of TURN
fivetuple = (sock.type, getlocaladdr(sock), remote)
try:
if fivetuple not in binding: # not found
raise ValueError, "no turn binding found"
newsock = binding[fivetuple]
destaddr = Attribute.DESTINATION_ADDRESS in m and m[Attribute.DESTINATION_ADDRESS].address[1:] or None
data = Attribute.DATA in m and m[Attribute.DATA] or None
if sock.type == socket.SOCK_STREAM:
try:
remote = newsock.getpeername()
except:
remote = None
if not remote:
newsock.connect(destaddr)
remote = destaddr
yield multitask.send(newsock, data)
else:
yield multitask.sendto(newsock, data, destaddr)
# TODO: we don't lock to destaddr. This is a security risk.
result = True
except:
if _debug:
print "sendRequest() exception", sys.exc_info()
result = False
res = Message()
res.method, res.type, res.tid = m.method, (result and Message.RESPONSE or Message.ERROR), m.tid
if not result:
error = Attribute(Attribute.ERROR_CODE)
error.error = (400, "cannot send request") # TODO: be more explicit.
res.attrs.append(error)
yield respond(sock, str(res), remote)
def datahandler(sock, data, remote): # handle a new data from given remote (ip, port)
try:
m = Message(data) # parse the message
func = (
m.type == Message.REQUEST
and (
m.method == Message.BINDING
and bindingRequest
or m.method == Message.ALLOCATE
and allocateRequest
or m.method == Message.SEND
and sendRequest
)
or None
)
if func:
yield func(sock, m, remote)
else:
raise ValueError, "unhandled request or message"
except StopIteration:
if _debug:
print "datahandler: stop iteration"
raise
except: # parsing error or unhandled message
if _debug:
print "datahandler() exception", sys.exc_info()
if handler:
handler(sock, remote, data) # invoke the application's handler.
def tcpreceiver(sock, remote): # handle a new incoming TCP connection
while True:
data = (yield multitask.recv(sock, maxsize))
if not data:
break # socket closed
type, length, magic = struct.unpack("!HHL", data[:8])
valid = (type & 0xC000 == 0) and magic == Message.MAGIC and length <= (maxsize - 8) # valid
if valid:
yield datahandler(sock, data, remote)
if _debug:
print "tcpreceiver() finished data handler"
else:
handler(sock, data, remote)
if tcp:
sock1.listen(5) # create the listen queue
if _debug:
print "server listening on", addr1
while True: # start the main listening loop of the server
try:
tcp = sock1.type == socket.SOCK_STREAM
except:
break # probably a bad file descriptor because sock1 is closed.
try:
if tcp:
conn, remote = (yield multitask.accept(sock1, timeout=5))
if conn:
if _debug:
print "server().accept() from", remote
multitask.add(tcpreceiver(conn, remote))
else:
data, remote = (yield multitask.recvfrom(sock1, maxsize, timeout=5)) # receive a packet
if data:
if _debug:
print "server().recvfrom() from", remote
multitask.add(datahandler(sock1, data, remote))
except multitask.Timeout:
continue
except: # some other socket error, probably sock1 is closed.
break
if _debug:
print "server() exiting"
def request(sock, server=None, **kwargs):
"""Send a STUN client request with retransmissions and return the response.
This is a generator function, and can be called as
response, external = yield request(sock, ('stun.iptel.org', 3478))
It raises ValueError in case of failure and multitask.Timeout in case of timeout
or failure to connect TCP or invalid response received. For TCP, the sock remains
connected after successful return or exception from this function.
Arguments are as follows:
sock: the socket to use for sending request and receiving response.
server: optional server (ip, port), defaults to defaultServers[0]. For TCP if sock
is already connected, then server argument is ignored.
method: optional STUN method, defaults to Message.BINDING.
tid: optional transaction id, by default generates a new.
attrs: optional attributes, by default empty list [].
rto: optional RTO, defaults to 0.1 for UDP and 9.3 for TCP.
retry: optional retry count, defaults to 7 for UDP and 1 for TCP.
maxsize: optional maximum packet size, defaults to 1500.
handler: optional handler function, that receives any message that was received
but not handled by the request method.
The handler argument allows demultiplexing other types of received messages on the
same socket. Note that raising an exception is not good, because we still want to
wait for response instead of exiting. The handler is invoked as
handler(sock, remote, data) where data is raw data string and remote is usually
server (ip, port). If no handler is specified, then invalid data raises a ValueError.
"""
server = server or defaultServers[0] # use first server if missing
handler = kwargs.get("handler", None)
maxsize = kwargs.get("maxsize", 1500)
m = Message()
m.method = kwargs.get("method", Message.BINDING)
m.type = Message.REQUEST
m.tid = kwargs.get("tid", urandom(12))
m.attrs = kwargs.get("attrs", [])
mstr = str(m) # formatted message bytes to send
if len(mstr) >= maxsize:
raise ValueError, "Cannot send packet of length>%d" % (maxsize)
if sock.type == socket.SOCK_STREAM:
remote = None
try:
remote = sock.getpeername()
except:
pass
if not remote:
try:
sock.connect(server)
remote = server # connect if not already connected.
except:
raise multitask.Timeout() # can't connect, then raise a timeout error.
tcp, rto, retry = True, kwargs.get("rto", 9.3), kwargs.get("retry", 1)
else:
tcp, rto, retry = False, kwargs.get("rto", 0.100), kwargs.get("retry", 7)
while retry > 0:
retry = retry - 1
if _debug:
print "sending STUN request method=%d, len=%d, remaining-retry=%d" % (m.method, len(mstr), retry)
if tcp:
yield multitask.send(sock, mstr) # send the request
else:
yield multitask.sendto(sock, mstr, server)
try:
if tcp: # receiving a TCP packet is complicated. remote is already set
data = (yield multitask.recv(sock, maxsize, timeout=rto))
if not data:
break
if _debug:
print "request() received data"
type, length, magic = struct.unpack("!HHL", data[:8])
if type & 0xC000 != 0 or magic != Message.MAGIC:
raise ValueError, "invalid STUN response from server type=0x%x, magic=0x%x" % (type, magic)
if length > (maxsize - 8):
raise ValueError, "very large response length[%d]>%d" % (length + 8, maxsize)
else: # receive a UDP datagram
data, remote = (yield multitask.recvfrom(sock, maxsize, timeout=rto))
if data:
try:
response = Message(data) # parse the message if any
if _debug:
print "received STUN message method=%d, type=%d" % (response.method, response.type)
except:
if _debug:
print "received invalid STUN message len=%d" % (len(response))
if handler:
handler(sock, remote, data) # allow app to demultiplex
continue # retry next
else:
raise ValueError, "Invalid response from server"
if response.tid != m.tid:
if _debug:
print "The tid does not match. ignoring"
if handler:
handler(sock, remote, data)
continue # probably a old response, don't raise exception.
external = None
for attr in response.attrs:
if not attr.optional and attr.type not in Attribute.knownTypes:
raise ValueError, "Attribute 0x%04x not understood in response" % attr.type
if response.type == Message.RESPONSE: # success response
for attr in response.attrs:
if m.method == Message.BINDING:
if attr.type == Attribute.XOR_MAPPED_ADDRESS:
external = attr.xorAddress # (family, ip, port)
elif attr.type == Attribute.MAPPED_ADDRESS: # for backward compatibility with RFC 3489
external = attr.address
elif response.type == Message.ERROR: # error response
error = None
for attr in response.attrs:
if attrs.type == Attribute.ERROR_CODE:
error = attrs.error # (code, reason)
break
raise ValueError, "Request failed with error %r" % error
if external:
external = external[1:] # ignore the address family
raise StopIteration(response, external) # result to the caller
# TODO: else do we continue or raise an error?
except multitask.Timeout:
rto = rto * 2 # double the rto
except StopIteration:
if _debug:
print "request() returning external=" + str(external)
raise
except: # any other exception, fall back to Timeout exception
if _debug:
print "Some ValueError exception", sys.exc_info()
break
raise multitask.Timeout # no response after all retransmissions
def server(sock1, **kwargs):
'''A simple server implementation to test the code or to use in real deployment.
The application should start the server as multitask.add(server(sock)).
The caller should make sure that the sock1 argument is a UDP or TCP socket
which is already bound. Additionally, sock2, sock3, and sock4 can be supplied
as keyword arguments and represent the socket to use for change-IP, change-port
and change IP+port commands respectively. Other keyword arguments are as follows:
timeout: optional acivity timeout (second) if relay is activated, defaults to 180.
external: optional external (ip, port) of the socket in case it is behind
a full-cone NAT and still acts as a (relay) server.
handler: optional function that gets invoked as handler(sock, remote, data) for
non-STUN data, and allows the application to demultiplex other types of data.
maxsize: optional maximum size of packet to handle, defaults to 1500.'''
sock2, sock3, sock4 = kwargs.get('sock2', None), kwargs.get(
'sock3', None), kwargs.get('sock4', None)
addr1 = getlocaladdr(sock1)
addr4 = sock4 and getlocaladdr(sock4) or None
timeout = kwargs.get('timeout', 180) # three minutes
external = kwargs.get('external', addr1)
handler = kwargs.get('handler', None)
maxsize = kwargs.get('maxsize', 1500)
tcp = (sock1.type == socket.SOCK_STREAM
) # whether the server is on tcp or udp.
binding = dict() # allocated relay bindings if any
def respond(sock, data, remote):
if sock.type == socket.SOCK_STREAM:
yield multitask.send(sock, data)
else:
yield multitask.sendto(sock, data, remote)
def bindingRequest(sock, m, remote): # Serve a binding request of STUN
res = Message()
res.method, res.type, res.tid = Message.BINDING, Message.RESPONSE, m.tid
mapped = Attribute(
Attribute.MAPPED_ADDRESS) # mapped-address attribute
mapped.address = (sock.family, addr1[0], addr1[1])
res.attrs.append(mapped)
if Attribute.CHANGE_REQUEST not in m: # send from same address:port
if addr4: # add the other address attribute
other = Attribute(Attribute.OTHER_ADDRESS)
other.address = (sock4.family, addr4[0], addr4[1])
res.attrs.append(other)
else:
change = m[Attribute.CHANGE_REQUEST]
sock = change.value == '\x00\x00\x00\x06' and sock4 or change.value == '\x00\x00\x00\x02' and sock3 or change.value == '\x00\x00\x00\x04' and sock2 or None
if sock:
yield respond(sock, str(res), remote)
raise StopIteration()
def allocateRequest(sock, m, remote): # serve the allocate request of TURN
fivetuple = (sock.type, getlocaladdr(sock), remote)
lifetime = timeout
if Attribute.LIFETIME in m:
lt = struct.unpack('!L', m[Attribute.LIFETIME].value)
if lt < lifetime: lifetime = lt
if fivetuple in binding: # already found
newsock = binding[fivetuple]
if lifetime == 0: # terminate the binding
del binding[fivetuple]
del binding[newsock]
else:
if lifetime > 0: # allocate, otherwise it is already missing.
newsock = socket.socket(sock.family, sock.type)
newsock.bind(('0.0.0.0', 0)) # bind to any
binding[newsock] = fivetuple
binding[fivetuple] = newsock
res = Message()
res.method, res.type, res.tid = m.method, Message.RESPONSE, m.tid
mapped = Attribute(
Attribute.MAPPED_ADDRESS) # mapped-address attribute
mapped.address = (newsock.family,
(external, newsock and newsock.getsockname()[1]
or 0))
res.attrs.append(mapped)
res.attrs.append(
Attribute(Attribute.LIFETIME, struct.pack('!L', lifetime)))
if lifetime == 0 and newsock: # close any previous listening function
newsock.close() # this should trigger close of functions
else:
if sock.type == socket.SOCK_STREAM:
multitask.add(relayaccepter(newsock, fivetuple))
else:
multitask.add(relayreceiver(newsock, fivetuple))
yield respond(sock, str(res), remote)
def relaytcpreceiver(sock, fivetuple):
pass
def relayaccepter(sock, fivetuple):
sock.listen(5) # accept queue
while True: # start the main listening loop of the tcp server
try:
conn, remote = (yield multitask.accept(sock))
if conn:
if _debug: print 'relayaccepter().accept() from', remote
sock.close(
) # close the original listening socket -- no more connections
binding[fivetuple] = conn # update the binding
del binding[sock]
binding[conn] = fivetuple
multitask.add(relaytcpreceiver(conn, fivetuple, remote))
break
except: # some other socket error, probably sock is closed.
break
if _debug: print 'relaytcpaccepter() exiting'
def relayreceiver(sock, fivetuple):
while True: # start the main listening loop of the udp server
try:
data, remote = (yield multitask.recvfrom(sock, maxsize)
) # receive a packet
if data:
if _debug: print 'server().recvfrom() from', remote
multitask.add(datahandler(sock1, data, remote))
except: # some other socket error, probably sock1 is closed.
break
if _debug: print 'server() exiting'
def sendRequest(sock, m, remote): # serve the send request of TURN
fivetuple = (sock.type, getlocaladdr(sock), remote)
try:
if fivetuple not in binding: # not found
raise ValueError, 'no turn binding found'
newsock = binding[fivetuple]
destaddr = Attribute.DESTINATION_ADDRESS in m and m[
Attribute.DESTINATION_ADDRESS].address[1:] or None
data = Attribute.DATA in m and m[Attribute.DATA] or None
if sock.type == socket.SOCK_STREAM:
try:
remote = newsock.getpeername()
except:
remote = None
if not remote:
newsock.connect(destaddr)
remote = destaddr
yield multitask.send(newsock, data)
else:
yield multitask.sendto(newsock, data, destaddr)
# TODO: we don't lock to destaddr. This is a security risk.
result = True
except:
if _debug: print 'sendRequest() exception', sys.exc_info()
result = False
res = Message()
res.method, res.type, res.tid = m.method, (result and Message.RESPONSE
or Message.ERROR), m.tid
if not result:
error = Attribute(Attribute.ERROR_CODE)
error.error = (400, 'cannot send request'
) # TODO: be more explicit.
res.attrs.append(error)
yield respond(sock, str(res), remote)
def datahandler(sock, data,
remote): #handle a new data from given remote (ip, port)
try:
m = Message(data) # parse the message
func = m.type == Message.REQUEST and ( \
m.method == Message.BINDING and bindingRequest \
or m.method == Message.ALLOCATE and allocateRequest \
or m.method == Message.SEND and sendRequest \
) or None
if func:
yield func(sock, m, remote)
else:
raise ValueError, 'unhandled request or message'
except StopIteration:
if _debug: print 'datahandler: stop iteration'
raise
except: # parsing error or unhandled message
if _debug: print 'datahandler() exception', sys.exc_info()
if handler:
handler(sock, remote,
data) # invoke the application's handler.
def tcpreceiver(sock, remote): # handle a new incoming TCP connection
while True:
data = (yield multitask.recv(sock, maxsize))
if not data: break # socket closed
type, length, magic = struct.unpack('!HHL', data[:8])
valid = (type & 0xC000
== 0) and magic == Message.MAGIC and length <= (
maxsize - 8) # valid
if valid:
yield datahandler(sock, data, remote)
if _debug: print 'tcpreceiver() finished data handler'
else:
handler(sock, data, remote)
if tcp: sock1.listen(5) # create the listen queue
if _debug: print 'server listening on', addr1
while True: # start the main listening loop of the server
try:
tcp = (sock1.type == socket.SOCK_STREAM)
except:
break # probably a bad file descriptor because sock1 is closed.
try:
if tcp:
conn, remote = (yield multitask.accept(sock1, timeout=5))
if conn:
if _debug: print 'server().accept() from', remote
multitask.add(tcpreceiver(conn, remote))
else:
data, remote = (yield multitask.recvfrom(sock1,
maxsize,
timeout=5)
) # receive a packet
if data:
if _debug: print 'server().recvfrom() from', remote
multitask.add(datahandler(sock1, data, remote))
except multitask.Timeout:
continue
except: # some other socket error, probably sock1 is closed.
break
if _debug: print 'server() exiting'
def request(sock, server=None, **kwargs):
'''Send a STUN client request with retransmissions and return the response.
This is a generator function, and can be called as
response, external = yield request(sock, ('stun.iptel.org', 3478))
It raises ValueError in case of failure and multitask.Timeout in case of timeout
or failure to connect TCP or invalid response received. For TCP, the sock remains
connected after successful return or exception from this function.
Arguments are as follows:
sock: the socket to use for sending request and receiving response.
server: optional server (ip, port), defaults to defaultServers[0]. For TCP if sock
is already connected, then server argument is ignored.
method: optional STUN method, defaults to Message.BINDING.
tid: optional transaction id, by default generates a new.
attrs: optional attributes, by default empty list [].
rto: optional RTO, defaults to 0.1 for UDP and 9.3 for TCP.
retry: optional retry count, defaults to 7 for UDP and 1 for TCP.
maxsize: optional maximum packet size, defaults to 1500.
handler: optional handler function, that receives any message that was received
but not handled by the request method.
The handler argument allows demultiplexing other types of received messages on the
same socket. Note that raising an exception is not good, because we still want to
wait for response instead of exiting. The handler is invoked as
handler(sock, remote, data) where data is raw data string and remote is usually
server (ip, port). If no handler is specified, then invalid data raises a ValueError.
'''
server = server or defaultServers[0] # use first server if missing
handler = kwargs.get('handler', None)
maxsize = kwargs.get('maxsize', 1500)
m = Message()
m.method = kwargs.get('method', Message.BINDING)
m.type = Message.REQUEST
m.tid = kwargs.get('tid', urandom(12))
m.attrs = kwargs.get('attrs', [])
mstr = str(m) # formatted message bytes to send
if len(mstr) >= maxsize:
raise ValueError, 'Cannot send packet of length>%d' % (maxsize)
if sock.type == socket.SOCK_STREAM:
remote = None
try:
remote = sock.getpeername()
except:
pass
if not remote:
try:
sock.connect(server)
remote = server # connect if not already connected.
except:
raise multitask.Timeout(
) # can't connect, then raise a timeout error.
tcp, rto, retry = True, kwargs.get('rto', 9.3), kwargs.get('retry', 1)
else:
tcp, rto, retry = False, kwargs.get('rto',
0.100), kwargs.get('retry', 7)
while retry > 0:
retry = retry - 1
if _debug:
print 'sending STUN request method=%d, len=%d, remaining-retry=%d' % (
m.method, len(mstr), retry)
if tcp:
yield multitask.send(sock, mstr) # send the request
else:
yield multitask.sendto(sock, mstr, server)
try:
if tcp: # receiving a TCP packet is complicated. remote is already set
data = (yield multitask.recv(sock, maxsize, timeout=rto))
if not data: break
if _debug: print 'request() received data'
type, length, magic = struct.unpack('!HHL', data[:8])
if type & 0xC000 != 0 or magic != Message.MAGIC:
raise ValueError, 'invalid STUN response from server type=0x%x, magic=0x%x' % (
type, magic)
if length > (maxsize - 8):
raise ValueError, 'very large response length[%d]>%d' % (
length + 8, maxsize)
else: # receive a UDP datagram
data, remote = (yield multitask.recvfrom(sock,
maxsize,
timeout=rto))
if data:
try:
response = Message(data) # parse the message if any
if _debug:
print 'received STUN message method=%d, type=%d' % (
response.method, response.type)
except:
if _debug:
print 'received invalid STUN message len=%d' % (
len(response))
if handler:
handler(sock, remote, data) # allow app to demultiplex
continue # retry next
else:
raise ValueError, 'Invalid response from server'
if response.tid != m.tid:
if _debug: print 'The tid does not match. ignoring'
if handler: handler(sock, remote, data)
continue # probably a old response, don't raise exception.
external = None
for attr in response.attrs:
if not attr.optional and attr.type not in Attribute.knownTypes:
raise ValueError, 'Attribute 0x%04x not understood in response' % attr.type
if response.type == Message.RESPONSE: # success response
for attr in response.attrs:
if m.method == Message.BINDING:
if attr.type == Attribute.XOR_MAPPED_ADDRESS:
external = attr.xorAddress # (family, ip, port)
elif attr.type == Attribute.MAPPED_ADDRESS: # for backward compatibility with RFC 3489
external = attr.address
elif response.type == Message.ERROR: # error response
error = None
for attr in response.attrs:
if attrs.type == Attribute.ERROR_CODE:
error = attrs.error # (code, reason)
break
raise ValueError, 'Request failed with error %r' % error
if external:
external = external[1:] # ignore the address family
raise StopIteration(response,
external) # result to the caller
# TODO: else do we continue or raise an error?
except multitask.Timeout:
rto = rto * 2 # double the rto
except StopIteration:
if _debug: print 'request() returning external=' + str(external)
raise
except: # any other exception, fall back to Timeout exception
if _debug: print 'Some ValueError exception', sys.exc_info()
break
raise multitask.Timeout # no response after all retransmissions
